musculoskeletal block pathology lecture 1: fracture and bone healing

MUSCULOSKELETAL BLOCK

PathologyLecture 1: Fracture and bone

healingDr. Maha Arafah

Dr. Abdulmalik Alsheikh, MD, FRCPC

Dec 11, 2011

MUSCULOSKELETAL BLOCK

Pathology: 5 lectures1. Fracture and bone healing2. Congenital and developmental bone

diseases3. Introduction to myopathies and

muscular dystrophy4. Non-infectious arthritis5. Osteomyelitis and septic arthritis

Healing of bone fractures

At the end of this lecture you should : Know the different types of fractures Be aware of the mechanism and stages

of fracture healing process Know the factors affecting healing

process and the possible complications of healing process

Appreciate the importance of road traffic accidents as a major cause of disability in Saudi Arabia

Normal anatomy

Parts of a long bones: epiphysis (ends of

bone, partially covered by articular cartilage)

physis (growth plate)

metaphysis (junction of diaphysis and epiphysis, most common site of primary bone tumors)

diaphysis (shaft)

Normal anatomy

Cross section: Periosteum cortex

(composed of cortical bone or compact bone)

medullary space (composed of cancellous or spongy bone)

Normal histology

Lamellar bone: layered bone with

concentric parallel lamellae

gradually replaces woven bone

normal type of bone found in adult skeleton

stronger than woven bone

Bone: mineralized osteoid; either lamellar bone or woven bone.

Osteoblasts: arise from marrow mesenchymal cells; when active, are plump and present on bone surface; eventually are encased within the collagen they produce.

Osteoclasts: large multinucleated cells found attached to the bone surface at sites of active bone resorption.

Fracture:- Break in the continuity of bone

Defintions.CompleteIncomplete

Defintions.

Closed fracture (simple).

Open fracture (compound).

Complicated fracture.

Defintions.Closed Fracture (simple ):-

Does NOT communicate with external environment

Defintions.Open Fracture (compound ):-

Communicate with external environment

Infection !!

Defintions.Complicated Fracture:-

Associated with damage to nerves, vessels or internal organs

Defintions.Fracture Dislocation:-

Always X-Ray Joint

Above and Below

Classification of fractures

Complete or incomplete Closed or compound Comminuted Displaced

Causes of fractures Traumatic fracture: Sever trauma Pathological fracture:

Fracture occur with minimal trauma the underlying bone is abnormal

e.g. Osteoporosis  Osteomalacia   Paget's disease of bone  Primary or metastatic tumor.

Stress fracture

Stress fracture

A stress fracture is generally an overuse injury. It occurs when muscles become fatigued or overloaded and can not absorb the stress and shock and repeated impact. Fatigued muscles transfer that stress to the nearby bone and the result is a small crack or fracture, in the bone.

Healing of fractures1. Reactive Phase

i Fracture and inflammatory phase ii. Granulation tissue formation

2. Reparative Phase iii. Callus formation iv. Lamellar bone deposition

3. Remodeling Phase v. Remodeling to original bone contour

Excellent Reduction with Well Molded Cast

How does a fracture heal? Stage 1: Inflammation Bleeding from the fractured bone and surrounding tissue causes the fractured area to swell. This stage begins the day you fracture the bone and lasts about 2 to 3 weeks.

Reparative Phase Soft callus 

Between 2 and 3 weeks after the injury, the pain and swelling will decrease. At this point, the site of the fracture stiffens and new bone begins to form. The new bone cannot be seen on x-rays. This stage usually lasts until 4 to 8 weeks after the injury.

Hard callus Between 4 and 8 weeks, the new bone begins to bridge the fracture. This bony bridge can be seen on X-rays. By 8 to 12 weeks after the injury, new bone has filled the fracture.

Bone remodeling Beginning about 8 to 1 2 weeks after the injury, the fracture site remodels itself, correcting any deformities that may remain as a result of the injury. This final stage of fracture healing can last up to several years.

The rate of healing and the ability to remodel a fractured bone vary tremendously for each person and depend on your age, your health, the kind of fracture, and the bone involved. For example, children are able to heal and remodel their fractures much faster than adults.

Fracture Healed

Time Factor- Perkin’s formula

Union Consolidation

Upper limb Spiral 3Transverse 6

6 weeks 12 =

Lower Limb Spiral 6Transverse 12

12 = 24 =

Children Half this time is needed

Healing of fractures Factors disrupting healing process:

Displaced and comminuted fractures Infection Vascular insufficiency Inadequate minerals and vitamins Inadequate immobilization

COMPLICATIONS Delayed union: A fracture

that takes longer to heal than expected is a delayed union.

Nonunion: A fracture that fails to heal in a reasonable amount of time is called a nonunion (pseudarthrosis)

COMPLICATIONS Delayed Union &

Non Union Causes:-

General:- Nutrition Bone Disease Old Age

COMPLICATIONS

Malunion:- Malunion: A fracture

that does not heal in a normal alignment is called a malunion

1- Primary Neglected #

2- After Reduction! Watch

X-Ray After 10 Days

COMPLICATIONSCompartment syndrome:

Severe swelling after a fracture can put so much pressure on the blood vessels that not enough blood can get to the muscles around the fracture.

The decreased blood supply can cause the muscles around the fracture to die, which can lead to long-term disability.

Compartment syndrome usually occurs only after a severe injury.

COMPLICATIONS  Neurovascular injury Infection: Open fractures can

become infected Post-traumatic

arthritis: Fractures that extend into the joints (intra-articular fractures) or fractures that cause the bones to meet at an abnormal angle in the joint can cause premature arthritis of a joint.

COMPLICATIONS Growth abnormalities: A fracture

in the open physis, or growth plate, in a child, can cause many problems.

Two of these problems are: premature partial or complete closure

of the physis. This means that one side of a bone or the whole bone stops growing before it naturally would.